Plant retention block



FIG. 1 is a perspective view showing a plant retention block;

FIG. 2 is a front elevational view of the plant retention block;

FIG. 3 is a rear elevational view of the plant retention block;

FIG. 4 is a top plan view of the plant retention block, the bottom plan view being a mirror image thereof; and,

FIG. 5 is an elevational view of a first side of the plant retention block, the second opposite side being a mirror image thereof.

The broken lines in FIGS. 1 and 4 are included for the purpose of illustrating portions of the plant retention block that form no part of the claimed design. 

CLAIM The ornamental design for a plant retention block, as shown and described. 